Critical analysis of fragment-orbital DFT schemes for the calculation of electronic coupling values

Abstract

We present a critical analysis of the popular fragment-orbital density-functional theory (FO-DFT) scheme for the calculation of electronic coupling values. We discuss the characteristics of different possible formulations or 'flavors' of the scheme which differ by the number of electrons in the calculation of the fragments and the construction of the Hamiltonian. In addition to two previously described variants based on neutral fragments, we present a third version taking a different route to the approximate diabatic state by explicitly considering charged fragments. In applying these FO-DFT flavors to the two molecular test sets HAB7 (electron transfer) and HAB11 (hole transfer) we find that our new scheme gives improved electronic couplings for HAB7 (-6.2% decrease in mean relative signed error) and greatly improved electronic couplings for HAB11 (-15.3% decrease in mean relative signed error). A systematic investigation of the influence of exact exchange on the electronic coupling values shows that the use of hybrid functionals in FO-DFT calculations improves the electronic couplings, giving values close to or even better than more sophisticated constrained DFT calculations. Comparing the accuracy and computational cost of each variant we devise simple rules to choose the best possible flavor depending on the task. For accuracy, our new scheme with charged-fragment calculations performs best, while numerically more efficient at reasonable accuracy is the variant with neutral fragments.

References in corpus (2)

• Embedded-Cluster Calculations in a Numeric Atomic Orbital Density-Functional Theory Framework
• Critical analysis of fragment-orbital DFT schemes for the calculation of electronic coupling values

Cited by in corpus (9)

• Challenges in Large Scale Quantum Mechanical Calculations
• Finding the Right Bricks for Molecular Lego: A Data Mining Approach to Organic Semiconductor Design
• Critical analysis of fragment-orbital DFT schemes for the calculation of electronic coupling values
• Genarris: Random Generation of Molecular Crystal Structures and Fast Screening with a Harris Approximation
• Accurate and efficient DFT-based diabatization for hole and electron transfer using absolutely localized molecular orbitals
• Excited state diabatization on the cheap using DFT: Photoinduced electron and hole transfer
• PyCDFT: A Python package for constrained density functional theory
• Interpreting Ultrafast Electron Transfer on Surfaces with a Converged First-Principles Newns-Anderson Chemisorption Function
• Investigating electron conductivity regimes in the bacterial cytochrome wire OmcS